Compounds having the following structural formulae are hereinafter identified by the ensuing chemical names or formula numbers. ##STR1##
The higher melting zeranol isomer is denominated ".alpha. zeranol" and assigned Formula No. III.A; the lower melting isomer is denominated ".beta. zeranol" and is assigned Formula No. III.B.
.alpha. and .beta. zeranol are useful anabolic and estrogenic substances for oral and parental administration to animals. See, e.g., U.S. Pat. Nos. 3,239,345 and 4,069,339. The pharmacology of .alpha. and .beta. zeranol and some derivatives thereof is discussed in Hidy, et al., Advances in Applied Microbiology 22:59-82 (1977).
Known methods for the production of .alpha. and .beta. zeranol entail surface, see--e.g., U.S. Pat. No. 3,239,345--or submerged--see e.g., U.S. Pat. No. 3,661,712--fermentation to yield a zeralenone (Formula I) metabolite. Zeralenone recovered from the fermentation product is hydrogenated to provide a mixture of the .alpha. and .beta. zeranol diastereomers. The diastereomers may be separated by fractional crystallization from isopropanol, see, e.g., U.S. Pat. No. 2,239,345, by esterification followed fractional crystallization, see, e.g., U.S. Pat. No. 3,687,912 or by liquid chromatography as described in EPO patent publication 0 248 916 and French patent 2,571,372. Mixtures of .alpha. and .beta. zeranol rich in the .beta. isomer may be recovered from the fractional crystallization mother liquor and dehydrogenated to provide a mixture of zeralanone, .alpha.-zeranol and .beta. zeranol which is recycled for hydrogenation concurrently with the zeralenone fermentation product, see, U.S. Pat. No. 3,960,898.